Unit testing internal methods in VS2017 .NET Standard library

According to .NET docs for the InternalsVisibleToAttribute:

The attribute is applied at the assembly level. This means that it can be included at the beginning of a source code file, or it can be included in the AssemblyInfo file in a Visual Studio project.

In other words, you can simply place it in your own arbitrarily named .cs file, and it should work fine:

// some .cs file included in your project
using System.Runtime.CompilerServices;
[assembly:InternalsVisibleTo("MyTests")]

As described here:

https://blog.sanderaernouts.com/make-internals-visible-with-new-csproj-format

It is possible to add the internal visible attribute within the project file by adding another ItemGroup:

<ItemGroup>
    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
        <_Parameter1>$(AssemblyName).Tests</_Parameter1>
    </AssemblyAttribute>
</ItemGroup>

or even:

<ItemGroup>
    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
        <_Parameter1>$(MSBuildProjectName).Tests</_Parameter1>
    </AssemblyAttribute>
</ItemGroup>

I like that solution because the project file seems to be the right place for defining such concerns.